The queen needed the complete heaven's blade for the upcoming war. So no matter how weak those two are compare to layfon. they are still needed. So Haia and Clara become heaven's blade. Heaven's blade unleash the full potential of a military artist because you won't be limited to the amount of kei you can unleash but for those two.... well let's just see what will happen. They are just average in kei level to begin with. their skills are only probably in heaven's blade level but the requirements for heaven's blade is skill + kei.